This invention concerns a special design of double cuff placed near the distal tip of endotracheal tubes. Conventionally, a single cuff is inflated with air following insertion of the device into the human mid-trachea to achieve an airtight seal of the space between the tube and surrounding tracheal wall. As such the cuffed endotracheal tube has been routinely employed for many decades to prevent upper airway obstruction or to facilitate artificial ventilation of the unconscious or anesthetized patient. However, recent investigations have disclosed several defects in conventional cuffed endotracheal tubes. The double cuff herein described overcomes all of the following defects. These defects are, firstly, the failure to prevent secretions from accumulating in the upper trachea. Secondly, all tracheal tubes traverse the delicate structures of the larynx and abrade the vocal cords as a result of to and fro motion of the tube associated with respiration. Thirdly, the effects of intra-cuff sealing pressure upon the ciliated membranes lining the tracheal wall reversibly or permanently injure the cilia and surface membranes of the mid-trachea. The degree of injury is proportional to the magnitude of lateral-wall-cuff pressure in excess of 15 centimeters of water and to the duration such pressure is applied. Conventionally, the inflatable cuff is placed to rest in the mid-trachea several contimeters below the larynx, where compression of the ciliated endothelium of the trachea causes injury. Conventional endotracheal tube cuffs have a single cavity and produce a non-leak seal at pressures which occlude the blood perfusion of the tracheal mucosa and after a period of time produce tissue necrosis. By contrast the present invention consists of two cuffs in series which provide a total assembly which anchor the tube at points immediately above and below the larynx, thereby preventing bronchial intubation and inadvertent extubation.
One problem arising from prevailing practices of tracheal intubation is the failure of the conventional cuff to prevent secretions from passing through an unprotected space between the vocal cords and the endotracheal tube. The result is accumulation of a ring of contaminated material in the upper trachea above the inflated cuff which enters the lung when the cuff is deflated at extubation. During intubation this residue or ring of infected secretions trickles into the larynx and becomes entrapped above the inflated cuff until subsequent extubation allows the ring of secretions to enter the mid-trachea where injured cilia fail to protect the lung. The normal protective mechanisms by which the cilia carry the secretions upward in the respiratory tree until reflex coughing results in their removal fail to operate. My invention eliminates such aspiration by virtue of placing the upper inflatable cuff immediately above the larynx to keep the upper airway secretions from entering the laryngeal area. After insertion and initial inflation the cuff rests above the larynx thereby preventing exposure of the larynx and trachea to contamination. By leaving inflated the cuff described here, oral secretions may be removed by suction catheter with both the larynx and trachea protected. Thus, the present invention is superior to the conventional single cuffs in at least three important features, as herein embodied: (1) a positive means of anchoring the cuff between the cords, thereby preventing tube motion, accidental extubation, or further penetration of the cuffed tube into a bronchus, (2) low sealing pressure within the trachea and above the larynx and (3) secretions are excluded from the larynx or upper trachea.